Switching between subjective and objective modes is the essence of the scientific modus operandi. Not many people seem to appreciate that. Science is all about riding two horses, maybe not in concert, but certainly alternately - and knowing when to switch from one to the other.

Friday, December 30, 2011

This is a quickie post. I'll tidy it up later. It's to show some comments I have today posted to Tom Chivers blog on the Daily Telegraph with the germ of an idea (that may or may not be original).

Tom's topic title:

The Shroud of Turin: forgery or divine? A scientist writes

The comments set out briefly an idea that came to me suddenly this afternoon as to how that image on the Turin Shroud may/might have been produced in the 14th century by medieval "forgers", intent on producing yet another 'holy relic' to add to fragments of the 'real cross' etc etc. Yes, holy relics were a major growth industry in the 14th century, given they could attract thousands of pilgrims to your cathedral or whatever each year - the beginnings of the travel industry...

The crucial detail is that the image is a negative, i.e. parts of the original object that were well illuminated ("light") look dark and vice versa.

A negative image might at first sight suggest some kind of photography, either early primitive, or entirely accidental, or a combination of the two.

Leaving aside the nature of the photographic emulsion and photosensitive compound there is a problem with production of any image by photography. It needs either a good convex (converging) lens to bring light rays to a focus, or failing that a pinhole camera. It seems improbable(though not impossible) that either of those technologies were available even 800 years ago at a sufficient state of development, since if there had been there would surely be a host of other artefacts available from that era (e.g. grainy photographs of royalty?).

But there is another means by which an image can be produced that does not need photography, or at any rate the focusing of light from an object. One could use 'thermo-stencilling" instead. How? By taking some white fabric, and fashioning an image using black charcoal as one would a portrait, using degrees of shading rather than a line image. One would then expose the cloth to radiant heat, say from a furnace. The black areas would absorb heat and partially scorch the cloth in immediate contact with the charcoal while the white areas would reflect light and remain unscorched. The final step would then be to wash the particles of charcoal completely out of the cloth, leaving just the brown image - and if I am not mistaken it would be a negative image, assuming the artist used the charcoal lightly for light-reflecting features of a man's body, and more heavily for the bas-relief features that are in partial shade or reflect less light Oops - sorry about that. Thanks Mouse (comments) for pointing out that silly error.

By washing out the charcoal, the observer sees no evidence of the the image having been "painted" on the cloth. All that is left is a scorch mark - and being formed under a charcoal coating, it may be subtly different perhaps from one formed by direct action of hot iron or heat rays onto fabric.

Comment 2 (omitted, largely clarification in response to a query from xxxxxxx)

Comment 3 - further clarification:

Sorry, xxxxxxx , but I don't understand your difficulty re charcoal. If you had been barbecuing, and had got charcoal dust on your shirt, would you throw your shirt away, on the assumption that it was impossible to wash out? Surely not. Even without modern detergents, charcoal, which is simply microcrystalline graphite, i.e. sheets of carbon atoms arranged as fused hexagons, giant molecules in fact, should be relatively easy to wash out.

You are not by any chance confusing charcoal with scorched or charred cloth by any chance? The procedure I propose starts by drawing on a cloth with the kind of charcoal given out in school art classes - carbonised twigs. The cloth is then "grilled", i.e. exposed to radiant heat, e.g. from red hot coals, or again, charcoal, though I hesitate to mention it, and the black, charcoal-coated areas on the cloth will heat up - and become scorched - in contrast to the white reflective areas without charcoal that will remain relatively unscorched, at least with short exposure times.

I only suggested charcoal because it is "right for the period" and probably does the job, but other black substances might serve equally well, given that black subsrtances absorb heat as well as light, provided they can be washed out after heating so as to "dispose of the evidence" so to speak as to how the negative image was produced. Please tell me if I am not making sense.

Again, I thank you for your interest, but have to say I am somewhat disappointed by the response so far. Any feasible mechanism should surely place a big question mark over the assertion of those Italian scientists that there is no known mechanism by which the image could have been produced. I maintain there is - and I have chosen to call it "thermo-stencilling".

Tomorrow I must get hold of some charcoal, and see whether or not the idea works as predicted. I'll use a hot ring on the cooker hob as a source of radiant heat.

Update: Saturday 31 Dec 2011 I've just this minute cut up some cotton pillowcase (OK, so it's not flax/linen as per original Turin Shroud) and then cut some batten as per piccy below to create grips - left and right - that allow the cloth to be held close to a source of radiant heat without barbecuing knuckles. Missus will add artist's charcoal to her shopping list when she goes into town this afternoon.

While waiting for the charcoal. I have been giving thought to what to use as a source of radiant heat. The initial idea was to use the cooker hob:

But there's a potential complication there - it's not just radiant heat, but hot rising convection currents as well. It's better to isolate and study one variable at a time.

The new ceiling spots in my bathroom throw off a lot of radiant heat - downwards - in the opposite direction from rising convection currents, so I will try holding my "miniature shroud" up close to a spot.

Update Sunday 1st Jan 2012

Well, missus was unable to get hold of artists' charcoal stick, but never mind, we'll try barbecue lump charcoal:

Watch this space folks (will try "grilling" under a spotlight as soon as missus has vacated the bathroom).

OK, so here's the charcoal outline being exposed to radiant heat from a ceiling spot, with the charcoal-side facing the lamp. Within a few minutes I began to see a sepia smile appearing on my side.

And here is the reverse side back on the table after just a few minutes of gentle grilling. Prediction confirmed! 'Thermo-stencilling' WORKS - and given the utter simplicity of the procedure may or might well have been the method used 800 years ago to produce the Turin Shroud.

The final step is to wash out the charcoal, leaving hopefully just the scorch mark (with no clue as to how it was formed!)

Here it is after a brief rub with soap and a rinse. Not all the charcoal is removed, but enough to see that the image is now mainly in the form of a scorch mark.

The final step is to dry over the heated towel rail:

Incidentally, if you are wondering why the whole face (and those ears) are not brown, it's because of the limited diameter of my ceiling spots. I used one (60W) in the living room - bigger than the bathroom I had originally intended to use but the diameter is still only 7cm approx.

What might have been used as a souce of heat 800 years ago? Maybe a kiln or furnace (lime? glass?) with the door open...

Have just this minute posted this to Tom Chivers blog:

"Hello again everyone (and a Happy New Year to Tom). Guess what? I have just reproduced a downmarket version of the "Turin Shroud" in miniature, using simply a cotton sheet, a lump of barbecue charcoal, a source of radiant heat and a bar of soap. It's all on my own science buzz blog:

Tuesday, April 5, 2011

The Guardian has invited readers with a relevant or specialist scientific background to suggest ideas for how the dire situation at Fukushima's crippled and leaking nuclear power station might be contained.

At present, the now highly-contaminated site is storing vast quantities of water that have been hosed in, a desperate and makeshift attempt to cool the reactor cores - and even spent fuel rods.

That is the dire situation that has arisen, following the breakdown in normal cooling systems. Fukushima has been hit with a double whammy from both earthquake and tsunami damage. The earthquake, at a massive 9.0 magnitude, damaged the reactor cores, and the tsunami knocked out power supply to the coolant systems.

It's easy to propose solutions, from the comfort of one's armchair, without worrying about one's exposure to hard penetrating radiation, but here, for what it is worth, is my advice, posting as sciencebod, to those brave workers, who suddenly find themselves in the wrong place and at the wrong time:

"First of all, stop thinking about quick fixes, panaceas etc. Fission products continue to give off decay heat long after the control rods are inserted to absorb neutrons and stop the chain reaction. Secondly, any leakage from reactor core sends the primary fission products – notably I -131 and Cs -137 into the air, which then get incorporated into the thyroid and other body tissues, bombarding with radiation from WITHIN, so the issue is one of containment – attempting to keep the nasties on site, while protecting the workers from external radiation (they are not at risk from internal, since the hazard of ingested I-131 and Cs-137 is well known and preventable).

So how does one contain, given there are accumulations of hosed water – a make-shift remedy in view of failed pumps etc – and cracks in concrete containment ponds etc?

Desperate situations call for desperate measures – remember Red Adair, and how liquid nitrogen was finally used to tame the Kuwaiti fires started by Saddam’s retreating troops.
The chief problem at present is radioactive contaminated water that has to be disposed of to free up space for more contaminated water. Dumping it in the ocean may seem acceptable, given the diluting power of the Pacific, but it is not. It is polluting the planet. Contaminated water must be kept on site for as long as possible. But how?

Here’s the answer. When you cool water, the ice that is first formed tends to be pure water. Dissolved substances tend to stay in the water that has not yet frozen. Import ice-making machines into Fukushima, powered of diesel generators, and then periodically drain off the highly radioactive liquid below the ice (remembering that ice floats on top) and store that on site. Flush the ice briefly with fresh water to cleanse of contaminants, then let it melt in situ, and run the weakly radioactive melt into the sea.

Nope, it’s not a panacea, just an Elastoplast job, but it might help preserve a shred of credibility for the nuclear industry if it can contain its problem, instead of using the sea as a convenient dump. And let’s not forget that not all nuclear reactors are situated on coastlines, so my “ice solution” might be one they should consider on inland river locations etc. in the event of a problem comparable to Fukushima.

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About Me

Colin Berry, aka sciencebod, is a retired PhD researcher/teacher/academic who has worked in industry, medical schools, schools, food and biomedical research (mainly in the UK, but also in W.Africa and the United States). He's best known for his work on RESISTANT STARCH, recently described as "the trendiest form of dietary fibre".
See also his specialist Shroud of Turin blog on www.shroudofturinwithoutallthehype.wordpress.com
with over 200 postings to date.

Create one's own blog (age, class, gender no barrier)

It's really quite straightforward. All one has to do is to click on the photograph with that nice young man. One can then be part of the frightfully interesting Blogger community in just a couple of jiffs.

Acknowledgment

What's the latest on the LHC?

LHC gets warning system upgrade : BBC 28 September 2009

Self-organization

From wiki entry on SELF ORGANIZATION: "As a result, processes considered part of thermodynamically open systems, such as biological processes that are constantly receiving, transforming and dissipating chemical energy (and even the earth itself which is constantly receiving and dissipating solar energy), can and do exhibit properties of self organization far from thermodynamic equilibrium."

How far away should your off-licence be for a bottle of wine to be energy-neutral?

What do these two have in common?

Answer: both arrived in this world about the same time. Sir Isaac Newton was born on 4th Jan 1643 (new style*). The Taj Mahal had a 20 year gestation period, centred on approximately the same year. Click on piccy for an older post .* Or Christmas Day, 1642, depending which dating system one uses.

Is interstellar space travel feasible?

The nearest star (more correctly, star system, since it's 3 stars, a binary and a smaller satellite star) is Alpha Centauri. The average distance from Earth is 4.3 light years. Suppose technology allows us one day to achieve an interstellar cruising speed of half the speed of light. A comfortable acceleration of g (simulating Earth's gravity) would take a year, with another year to slow down comfortably. The entire journey from Earth would take a minimum of 10 years approximately. Having arrived at one's destination, it would take 4.3 years to send a radio postcard (" Hello Mum and Dad. Have arrived safely, and am now looking for a habitable planet. Am hoping it's hiding behind Proxima. Have looked everywhere else... Would die for some Cheddar cheese... ")

Watch this space

It's a cheap and cheerful form of transcendental meditation.(experimenting with settings, actually)

What causes weather?

Could you answer that question in just 7 words, ie " weather is due to...? Need some help, " Weather is due to t- - u - - - - - - h - - - - - - o - t - - E- - - -'s s - - - - - - ." The National Curriculum (England and Wales) does have its uses, but there are many more such simple principles, expressed in a minimum of words, that could be usefully incorporated.

"Had there been a Beginning (there wasn't, as it happens), there would initially have been complete Nothingness. But just as Nature abhors a vacuum, it's totally gutted at the thought of Nothingness. I mean to say - how far does Nothingness extend, assuming it has one of more dimensions? It can't extend for an infinite distance, since that would be a physical impossibility. Nothingness, to avoid having infinite reach, coils up on itself to acquire finite dimensions. In so doing, it becomes Somethingness, which has a spring-like potential energy - the total energy in fact of the Universe.

From that potential energy, present in what we now call space, or space-time, which is anything but empty, is spawned all sub-atomic particles - both matter and antimatter. When those particles collide, they mutually annihilate to create photons.

The reverse can also happen under extreme conditions - two photons can collide to create matter and anti-matter. It is potential energy in the spring-coiled Universe that is our "Dark Energy. It may or may not have mass depending on conditions.

A moment when it has no mass is the instant of the Big Bang. Let me briefly explain. An oscillating universe switches between Big Bang and Big Crunch. With the latter gravitation pulls everything into a super blackhole which then becomes a singularity - a massively dense point in space-time.

What prevents it becoming infinitely small - a physical impossibility? Answer: friction. As the sub-atomic plasma contracts and grinds, heat is generated which cannot escape - being a black hole. The temperature rises, ie particles in the plasma move faster and faster. When they reach their maximum velocity - the speed of light- all particles are suddenly transformed into photons, which as we know have no true mass(at least, no rest mass: any mass they have is purely relativistic due to their speed).

Once the entire Universe is a super-concentration of photons, all the gravitational forces in the singularity collapse to zero, or nearly so, and the entire thing blows apart - a new Big Bang, to create yet another cycle (inflation, Big Crunch, implosion etc). The Big Bang creates not just sub-atomic particles - from photon-photon collisions, but space-time itself. To reiterate: that space-time is always suffused with the stored potential energy of our curled-up dimensions (Dark Energy)."